In this lab we will look at the minimum configuration required to build a redundant and high speed link between two Cisco switches.

Configuration
SW1(config)#interface range gigabitEthernet 0/0-1 ! SW1(config-if-range)#channel-protocol ? lacp Prepare interface for LACP protocol pagp Prepare interface for PAgP protocol SW1(config-if-range)#channel-protocol lacp ! SW1(config-if-range)#channel-group ? <1-255> Channel group number auto Enable LACP auto on this interface ! SW1(config-if-range)#channel-group 1 ? mode Etherchannel Mode of the interface ! SW1(config-if-range)#channel-group 1 mode ? active Enable LACP unconditionally auto Enable PAgP only if a PAgP device is detected desirable Enable PAgP unconditionally on Enable Etherchannel only passive Enable LACP only if a LACP device is detected ! SW1(config-if-range)#channel-group 1 mode active Creating a port-channel interface Port-channel 1 ! SW2(config)#interface range gigabitEthernet 0/0-1 ! SW2(config-if-range)#channel-protocol lacp SW2(config-if-range)#channel-group 1 mode active
Depending on your requirements you will need to use either active or passive.
Verification
SW1# *Oct 26 05:08:04.210: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to up *Oct 26 05:08:04.220: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up *Oct 26 05:08:07.008: %LINK-3-UPDOWN: Interface Port-channel1, changed state to up *Oct 26 05:08:08.008: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel1, changed state to up ! SW1#show etherchannel summary Flags: D - down P - bundled in port-channel I - stand-alone s - suspended H - Hot-standby (LACP only) R - Layer3 S - Layer2 U - in use N - not in use, no aggregation f - failed to allocate aggregator M - not in use, minimum links not met m - not in use, port not aggregated due to minimum links not met u - unsuitable for bundling w - waiting to be aggregated d - default port A - formed by Auto LAG Number of channel-groups in use: 1 Number of aggregators: 1 Group Port-channel Protocol Ports ------+-------------+-----------+----------------------------------------------- 1 Po1(SU) LACP Gi0/0(P) Gi0/1(P) ! SW1#show etherchannel detail Channel-group listing: ---------------------- Group: 1 ---------- Group state = L2 Ports: 2 Maxports = 4 Port-channels: 1 Max Port-channels = 4 Protocol: LACP Minimum Links: 0 Ports in the group: ------------------- Port: Gi0/0 ------------ Port state = Up Mstr Assoc In-Bndl Channel group = 1 Mode = Active Gcchange = - Port-channel = Po1 GC = - Pseudo port-channel = Po1 Port index = 0 Load = 0x00 Protocol = LACP Flags: S - Device is sending Slow LACPDUs F - Device is sending fast LACPDUs. A - Device is in active mode. P - Device is in passive mode. Local information: LACP port Admin Oper Port Port Port Flags State Priority Key Key Number State Gi0/0 SA bndl 32768 0x1 0x1 0x1 0x3D Partner's information: LACP port Admin Oper Port Port Port Flags Priority Dev ID Age key Key Number State Gi0/0 SA 32768 0c73.d669.8000 7s 0x0 0x1 0x1 0x3D Age of the port in the current state: 0d:00h:04m:35s Port: Gi0/1 ------------ Port state = Up Mstr Assoc In-Bndl Channel group = 1 Mode = Active Gcchange = - Port-channel = Po1 GC = - Pseudo port-channel = Po1 Port index = 0 Load = 0x00 Protocol = LACP Flags: S - Device is sending Slow LACPDUs F - Device is sending fast LACPDUs. A - Device is in active mode. P - Device is in passive mode. Local information: LACP port Admin Oper Port Port Port Flags State Priority Key Key Number State Gi0/1 SA bndl 32768 0x1 0x1 0x2 0x3D Partner's information: LACP port Admin Oper Port Port Port Flags Priority Dev ID Age key Key Number State Gi0/1 SA 32768 0c73.d669.8000 1s 0x0 0x1 0x2 0x3D Age of the port in the current state: 0d:00h:04m:33s Port-channels in the group: --------------------------- Port-channel: Po1 (Primary Aggregator) ------------ Age of the Port-channel = 0d:00h:07m:17s Logical slot/port = 16/0 Number of ports = 2 HotStandBy port = null Port state = Port-channel Ag-Inuse Protocol = LACP Port security = Disabled Ports in the Port-channel: Index Load Port EC state No of bits ------+------+------+------------------+----------- 0 00 Gi0/0 Active 0 0 00 Gi0/1 Active 0 Time since last port bundled: 0d:00h:04m:33s Gi0/1 ! SW1#show interfaces status Port Name Status Vlan Duplex Speed Type Po1 connected 1 a-full auto